1. Field of the Invention
The present invention relates to a method of fabricating a strained FET, and more particularly, to a method of increasing stress in an FET.
2. Description of the Prior Art
Reductions in the size and inherent features of semiconductor devices such as field-effect transistors (FETs) have enabled continued improvements in speed, performance, density, and cost per unit function of integrated circuits over the past few decades. In accordance with a design of the FET and one of the inherent characteristics thereof, modulating the length of a channel region underlying a gate between a source and a drain of an FET alters a resistance associated with the channel region, thereby affecting the performance of the FET.
To further enhance the performance of FETs, stresses may be introduced in the channel region of an FET to improve its carrier mobility. Stress in the FET induced by conventional methods cannot, however, fulfill speed demands required of modern FETs. Therefore, there are continued efforts to enhance stress in FETs to achieve greater carrier mobility.